Thread inspections are a necessary part of many manufacturing or quality control procedures. These thread inspections may involve the spinning of externally or internally threaded gauges into threaded holes or onto threaded studs, respectively. The threaded holes or studs may be integral parts of machines or just fastener parts, such as nuts or bolts.
Go and No-Go Gauges have been, conventionally, used as screw thread inspection devices, throughout the machining industry, for the functional inspection for acceptable pitch, diameter, lead angle, thread crest, and root dimensions of a thread.
It is further noted that, conventionally, power driven spindles, on which gauges are fitted, have been used to facilitate rapid and uniform testing of screw threads.
For example, U.S. Pat. No. 4,926,700 discloses a blind hole thread gauge using a modified commercial nut driver. U.S. Pat. No. 4,926,700 discloses the use of strain gauges to monitor torque during testing, as well as, sensing when a given hole has been tested to its proper depth. The entire content of U.S. Pat. No. 4,926,700 is hereby incorporated by reference.
In another example, U.S. Pat. No. 7,059,055 discloses a commercial tester for checking the presence of threads in blind holes. Both single spindle and multi-spindle devices are described, which use adjustable slip clutches to limit the torque applied during testing. Upon detecting the proper depth of testing or upon exceeding the torque limit, U.S. Pat. No. 7,059,055 discloses that the tester automatically reverses the drive motor to disengage the gauge from the hole being tested. The entire content of U.S. Pat. No. 7,059,055 is hereby incorporated by reference.
In further examples, U.S. Pat. No. 7,661,196 and U.S. Pat. No. 7,941,932 disclose a compact hand-held ergonomic thread inspection tool that is power driven, which uses current draw or a mechanical clutch, as a surrogate for torque, to initiate automatic reversal and gauge withdrawal in case of jamming. U.S. Pat. No. 7,661,196 and U.S. Pat. No. 7,941,932 disclose that if a maximum torque is reached before a limit sensor is tripped, an alarm is initiated (indicating a defective thread), and the rotation of the thread gauge is reversed.
In other words, U.S. Pat. No. 7,661,196 and U.S. Pat. No. 7,941,932 determine if a threaded hole or stud is too short, the threads are untrue, or the threaded hole or stud is skewed away from the desired axis. The entire contents of U.S. Pat. No. 7,661,196 and U.S. Pat. No. 7,941,932 are hereby incorporated by reference.
As noted above, parts containing blind machined threaded bores often require inspection of the threads to verify for consistency before the machined parts can be shipped or assembled.
For example, the machining specification for a machined threaded bore may call for the machined threaded bore to have between 5.5 and 6.5 turns. In other words, if the machined threaded bore is outside the specified range, the machined threaded bore may be considered defective in view of the machining specifications.
If the machining specification calls for such a specific turn count, the above noted examples may be able to determine if one boundary (under threaded) of the range is met, but these conventional device are not able to determine if the other boundary (over threaded) of the range is met.
Conventionally, when the specification calls for a specific turn count into the bore, the inspection is carried out by a quality control technician, who manually counts the number of turns of the gauge to validate the thread length. However, this conventional counting method presents many issues.
With respect to quality assurance, since the counting is done manually by a quality control technician, the quality control technician may generate a false count if the quality control technician loses count or focus during the procedure. This is especially true when monitoring a large number of turns on a plurality of parts.
Moreover, due to the repetitive manual (turning) nature of the conventional counting technique, a quality control technician is more susceptible to carpal tunnel syndrome.
Therefore, it is desirable to provide a process and/or device for determining if a specific turn count specification has been met, which does not rely upon the manual counting of a quality control technician.
Moreover, it is desirable to provide an ergonomic process and/or device for determining if a specific turn count specification has been met, which is ergonomically designed to reduce the technician's susceptibility to carpal tunnel syndrome.
Furthermore, it is desirable to provide an ergonomic process and/or device for determining if a specific turn count specification has been met, which does not rely upon the manual counting of a quality control technician and is ergonomically designed to reduce the technician's susceptibility to carpal tunnel syndrome.